16 ON CEETAIN SERIES OF SECTIONS OF THE 



{A ) A .[B ) B,{C ) C,{D ) D, 



^ IS a 111 ^ .\',i ^ .1,1 ^ J ,1 ' 



{A ) A , (B ) B, (C ) C, {JJ ) I), 



C II {■!] ■ C n ^ Jill ^ It,, ' 



{A ) A ,{B ) B, {C ) C, {JJ ) JJ, 



^ I) I, (i) ^ b ,1 ^ I) I, ' ^ (:,i ' 



J (D ),B' [U \ C {1}\ V (C\, 



II A „ II ,1 (. II U i\i) 



A\{A'^j,jr^{jr^), c\{c\, D'UJ'x^^^^, 



A'{A''),B' (B' ) , c' {C' ) ,J)'{/J' )"\ 

 A' (A' ), B' {jr ) , C {C ) , JJ (D' ) . 



Diagram III. 



{A ) ,{B ),{C ),{D ), 



^ /(All ^ a' ^ A ' ^ A ' 



{A ) ,{B ), {C ), (Z> ), 



(-■ (2) ^ i. II II 



{A ) ,{B ), (C ),{D ), 

 (AB) (AAJ) , (AB) {AB) , 



iAc^ycy,iAC)^x^K\^, 

 iAB)^Uj\AAjy)^iAjy)^^^, 



(BO^XBY'), {BC)^XBC\ 

 {BJJ)^{B-D), {BD)^,{BD\ 



{CJj)^,{&iy), {r/j)^xr'jf). 



(-^^^)/^".),.i.' (^^'H^^',;„.v (^'^^i(^;.)„o/ (^^^A^^'j' (^^^^)^^;.)' (^'^h^'J' 



^^^^V^'aU' (^^^'),/^;.)„.' ^^^\S^'iiU ^^^^')/^'J' i^^AM".> ^msB\,), 



A'\{A' ),]3'\{JÏ ), C'\{C' ), J)'\{]J' ) , 



2 II 2 ,1 2 A V^ AU2:ii 



A'\{A' ),B'\{B' ) , 6'' 1(6" ) ,IJ'iiB' n , 

 Â\{A ), 7i'i(5' ) , <7'i(6" ) , I)'\{n' ) . 



Diagram IV. 



{A' ), {B' ), (6" ), {IJ' ) , 



/; A ^ A A Ui'i) 



[A' ), {B' ) , (6" ) , {JJ' ) 



(^' ),{B' ) ,(6" ) ,(Z»' 



) 



di' 



